The research proposes to study altered immune responsiveness in mice infected with Ascaris suum and Trichinella spiralis. Experiments will be carried out to (1) determine mechanism(s) by which ascaris infection suppresses immune responsiveness using an in vitro primary antibody technique; (2) characterize a soluble substance, obtained from cultures of splenocytes from mice infected with T. spiralis, that suppresses immune responses; (3) determine the mechanism by which lymph nodes from mice infected with T. spiralis enhance immune responses; (4) determine the molecular specificity of the rabbit antiserum specific for the ascaris-induced phosphorylcholine idiotype and (5) determine whether antiphosphorylcholine antibodies play a role in immunity to ascaris infection.